Ring-Opening of 4-Isoxazolines: Competitive Formation of Enamino Derivatives and a,b-Enones
摘要:
Ring-opening of 3-substituted 4-isoxazolines, proceeding through the intermediate isoxazolinium salts, follows two competing reaction pathways leading to alpha,beta-enones and enamines respectively. The rearrangement courses can be controlled as a function of substitution pattern and experimental conditions.
QUINTEIRO M.; SEOANE C.; SOTO J. L., REV. ROUM. CHIM., 1979, 24, NO 6, 859-864
作者:QUINTEIRO M.、 SEOANE C.、 SOTO J. L.
DOI:——
日期:——
RUBIO, M. J.;SEOANE, C.;SOTO, J. L.;SUSAETA, A., LIEBIGS ANN. CHEM., 1986, N 1, 210-219
作者:RUBIO, M. J.、SEOANE, C.、SOTO, J. L.、SUSAETA, A.
DOI:——
日期:——
Benzylidene-Alpha-Dicarbonyl Compounds as Novel Uv Absorbers
申请人:Koch Oskar
公开号:US20080050319A1
公开(公告)日:2008-02-28
The use of a compound of the formula
wherein
R
1
-R
3
independently of one another are hydrogen, C
1
-C
8
-alkyl or C
1
-C
8
-alkoxy,
R
4
is COR, CO
2
R, CONR
2
, where R is C
1
-C
8
-alkyl or C
3
-C
8
-cycloalkyl
R
5
is H or C
1
-C
8
-alkyl,
R
6
is aryl, aryl substituted by up to three C
1
-C
8
-alkyl- or C
1
-C
8
-alkoxy, or C
3
-C
8
-cycloalkyl
as UV filters in cosmetic formulations, in particular in combination with UV filters from the group consisting of methoxycinnamate derivatives and/or dibenzoylmethane derivatives, with the proviso that R
5
is H if R
4
is COR, is described.
Ring-Opening of 4-Isoxazolines: Competitive Formation of Enamino Derivatives and a,b-Enones
Ring-opening of 3-substituted 4-isoxazolines, proceeding through the intermediate isoxazolinium salts, follows two competing reaction pathways leading to alpha,beta-enones and enamines respectively. The rearrangement courses can be controlled as a function of substitution pattern and experimental conditions.
Investigation of Substituent Effects on the Selectivity of 4π-Electrocyclization of 1,3-Diarylallylic Cations for the Formation of Highly Substituted Indenes
作者:Chris D. Smith、Gregory Rosocha、Leo Mui、Robert A. Batey
DOI:10.1021/jo100275q
日期:2010.7.16
meta position particularly favor cyclization. There was no obvious correlation of cyclization selectivity with calculated electron densities as has been suggested for electrophilicaromaticsubstitutionreactions. However, the calculated selectivities determined by a gas-phase (B3LYP/6-31G* + ZPVE) comparison of the relative rates of cyclization were in remarkably good agreement with the observed selectivities